Salix lasiolepis (Arroyo Willow) is a species of willow native to western and southwestern North America, in the United States from southern Washington and southwestern Idaho south to California and Texas, and in Mexico from Baja California east to Coahuila and south to Jalisco. It is commonly found growing in canyons, along pond shores, and in swamps.

It is a deciduous large shrub or small tree growing to 10 m tall. The shoots are yellowish-brown, densely hairy when young. The leaves are 3.5–12.5 cm long, broad lanceolate, green above, glaucous green below covered at first with whitish to rusty hairs below which gradually wear off through the summer. The flowers are yellow catkins 1.5–7 cm long, produced in early spring.

The name is occasionally mis-spelled "lasiolepsis".